Application filed February 21,- 1893. Serial No. 463,246. (No model!) To all whom it may concern..-

Be it known that I, PARIS EUGENE SINGER, of 6 Victoria Road, Kensington, London, England, have invented certain new and useful Improved Methods of Varying the Resistances of an Electric Circuit Specially Applicable to Musical Instruments, of which the following is a specification.

The object of my invention is to enable a performer on a musical instrument actuated by electricity, to vary the intensity of any note by increasing the pressure of the finger on the key by which it is sounded.

In carrying out my invention, I place a receptacle containing a quantity of carbon powder, or equivalent material, in proximity to each key, and so arrange it that the depression of a key will, through the interposed carbon, close the electric circuit which operates the instrument. Further pressure on the key will, by compressing the carbon powder, lessen the resistance, and thereby intensify the sound.

The accompanying drawing shows so much of an electrical pianoforte as will serve to explain the manner of carrying out my invention.

A is the pianoforte key, fitted with a contact spring a, in electrical connection with the battery.

B is a plank running across the pianoforte immediately below the keys, in which are bored out cylindrical recesses or chambers (one for eachkey) to receive the carbon filling which is to form a link in each key circuit. b is a disk of ebonite, fitting the bottom of the recess in the plank B, and carrying a metal plate 19* in contact with the wire that leads from the battery. Resting upon the disk b, is a rigid tube 0, which serves to contain a tube d of india rubber, which is charged with carbon powder. This tube (Z stands up somewhat higher than the tube 0, and above it is placed an ebonite disk 12', which carries a metal plate 5 on its upper side, and a metal plate W on its under side, the two plates being connected together by a rod (2, which extends deep down into the carbon powder, for the purpose to be presently explained.

The disk I) is supported by a helical spring f, which surrounds the tube 0, and occupies the space between it and the cylindrical recess in the plank B. It will now be understood, that if pressure is put upon the key A by the finger of the player, the spring a will press upon the metallic plate 79" of the disk b, cause the springf to yield, and bring the metal plate W down upon the carbon in the elastic tube (1, and compress the carbon therein. This compression of the powdered carbon will, in proportion to the energy exerted by the player, establish a circuit of more or less resistance, and thereby vary the intensity of the note sounded as desired.

To prevent the powdered carbon becoming solidified by the repeated pressure to which it is to be subjected, the rod c is fitted with radial arms, which, through the endwise movement of the rod up and down in the tube (Z, will loosen or disintegrate the powdered carbon and prevent it caking.

I may remark that, in place of the powdered carbon, small disks or pellets of carbon may be employed, the same being placed in the tubular receptacle d, and pressed upon by the metallic plate 11 \Vhat I claim is- In a stringed musical instrument actuated by electricity under the control of finger keys, a yielding or elastic contact maker, consisting of granules, disks, or pellets of carbon or equivalent material, contained within, and supported by, a tube or chamber below the finger key, and connected with the battery wire, the carbon filling of such tube or chamber being exposed to electric contact with a metallic plate or button carried by the overlying finger key, as and for the purpose above set forth.